The present application is based on Japanese patent application No. 2011-159542 filed on Jul. 21, 2011, and the contents of the patent application are hereby incorporated by reference.
The present invention relates to a battery pack controller. More particularly, the invention relates to a battery pack controller which includes a closing control circuit for a main contactor that feeds a drive motor with electricity from a battery pack mounted on a vehicle such as an electric automobile.
It has been known that, in closing a main contactor (also termed “main relay”) which feeds a drive motor with electricity from a battery pack mounted on an electric automobile or a similar vehicle, an excessive initial charging current flows through a capacitor built in an inverter. This initial charging current can cause an obstacle to the protective function of a fuse or the like, or to damage the main contactor. Therefore, a precharge circuit which suppresses the initial charging current of the inverter is disposed. By way of example, the precharge circuit is connected in parallel with the main contactor which turns ON/OFF a power feed to the inverter. The precharge circuit has the function of limiting and feeding a charging current for a controller before the main contactor is closed, and closing the main contactor after the initial charging has been completed.
A battery pack controller is so formed that a main relay constituting the main contactor, the components of the precharge circuit and the components of any other control circuit are mounted on one surface of a base plate, and the wiring lines of the precharge circuit and the wiring lines of any other control circuit are laid on the other surface of the base plate. One of the pair of relay terminals of the main relay is connected to the electrode (for example, the positive electrode) of the battery pack, while the other relay terminal is connected to one input terminal of the inverter. In general, the battery pack controller is attached to the end part of the battery pack, and one relay terminal is directly connected to the electrode of the battery pack through a plate-like main circuit conductor (bus bar), while the other relay terminal is connected to a lead-out terminal by the main circuit bus bar. An electric wire terminal (a ring terminal, known as an LA terminal) which is connected to the inverter, is clamped to the lead-out terminal by a screw.
Meanwhile, the main wiring lines of the precharge circuit, which is connected in parallel with the main relay, are connected to one pair of main circuit bus bars which are in turn connected to one pair of relay terminals of the main relay. In a case where the main wiring lines of the precharge circuit are formed using bus bars (hereinbelow, termed “precharge-circuit bus bars”), the pair of main circuit bus bars and precharge-circuit bus bars are respectively clamped to the relay terminal portions by screws. Further, the entirety of the bus bars are protected in a manner to be surrounded with a resin-made protective cover (refer to, for example, Japanese Patent Publication No. JP-A-2009-289431). In a case where the main wiring lines of the precharge circuit are formed of electric wires instead of the bus bars, one pair of round terminals (a ring terminal, known as an LA terminals) connected to the electric wires are clamped to the pair of relay terminal portions by screws together with the pair of main circuit bus bars.
In the case where the main wiring lines of the precharge circuit are formed using the bus bars, the impulse noise of the ON/OFF of the main relay is sometimes amplified by the protective case, and hence, the reduction of the noise becomes a problem. On the other hand, in the case where the main wiring lines of the precharge circuit are formed of the electric wires, the main circuit bus bars and the LA terminals (i.e., ring terminals) with the electric wires are clamped to the relay terminal portions by the screws. Since, however, the LA terminal (i.e., ring terminal) turns and is difficult to position at the screw clamping, there is the problem of an inferior assemblability.
The problem that the invention intends to solve is to improve the assemblability of LA terminals (i.e., ring terminals) with electric wires, in forming the main wiring lines of a precharge circuit out of electric wires and reducing noise.